Telegraph system



Oct. 5 1926. 1,601,940

A. A. CLOKEY TELEGRAPH SYSTEM Original Filed Oct. 5,

//7 VI7TOFJ A///s0n A. C/okey Patented Oct. 5, 1926.

UNITED STATES PATENT OFFICE.

ALLISON A. CLOKEY, OF RUTHERFORD, NEW JERSEY. ASSIGNOR TO WESTERN ELEC- TRIC COMPANY, INCORPORATED, OF NEW YORK; N. Y., A CORPORATION OF NEW YORK.

TELEGRAPH SYSTEM.

Application filed October 3, 1922, Serial No. 582,010. Renewed July 12, 1926.

This invention relates to telegraph systems, and particularly to a high speed telegraph system adapted for use with long submarine cables.

It is an object of the invention to provide a high speed telegraph system capable of two way transmission without resorting to the ordinary duplex .method of operation, in which it is necessary to maintain a very accurate balance in order to insure satisfactory operation.

Another object of the invention is to provide suitable switching apparatus at the terminals of a long submarine cable to automatically and alternately associate the transmitters and receivers at the terminal stations with the cable conductors.

Ordinary submarine cables are not adapted to high speed signaling because of distortion of the signaling impulses due to the large distributed capacity of the cable conductors. In view of the many difficulties to be overcome, it has not been the practice to inductively load such cables to overcome the effect of the large distributed capacity. However, a certain nickel iron alloy, which has appropriately been termed permalloy, when properly prepared and made into a ribbon of spirally upon the cable conductor in the proper way, makes it possible to transmit legible signals over a long submarine cable at very much greater speed than has been possible heretofore. However, when transmitting signal impulses at the speed permissible with such a cable, difliculty arises due to inability to obtain or maintain a sufficiently accurate balance to permit duplex op eration.

In patent to John J. Gilbert, 1,586,895, issued June 1, 1926, there is described a method of two way operation which does not depend upon the conjugate relationship of transmitter and receiver as does the ordinary duplex method of operation. The present invention utilizes the same fundamental principle of operation as the Gilbert system.

Signaling impulses are propagated over a loaded submarine cable as current waves at relatively low velocity so that an appreciable period of a few tenths of a second elapses between the time when the transmitproper proportions and laid stations with the cable conductor for a period of time not greater than that required for the sending impulse at one station to reach the receiver at the other station. The receivers are then associated with the cable conductor for a substantially equal period of time. In accordance with another feature of the invention the switching mechanisms are arranged to associate a sending condenser with either end of the cable durmg the sending period and to associate a sha ing network with either end of the cable during the time allotted for the receiving of signal impulses.

The invention will be more clearlyunderstood by reference to the accompanying drawing, in which the single figure shows schematically the apparatus of a high speed two way telegraph system adapted for two channel sending and receiving of signals.

Referring now to .the drawing, there is disclosed a telegraph system consisting of terminal stations A and B joined by the cable G. Each terminal station is provided with a special rotary distributor, these distributors being arranged to rotate in synchronism in accordance with means wellknown in the art. One section of each distributor is divided equally into sending and receiving segments, Which are connected respectively to sending and receiving mechanisms. The time required for the distributor brush to make a complete revolution is equal to twice the time taken by a transmitted impulse to traverse the cable and reach the receiver. In the arrangement, as illustrated, two channels areprovided for the transmissionof impulses and two channels are likewise provided for the receiving and recording of impulses. The number of channels to be employed for efficient operation depends upon the characteristics of the cable, which determine the time required for a transmitted signal to reach the receiver. Since, for efficient operation, it is desirable to operate the transmitting and receiving mechanisms at as near as pos*' sible their maximum speeds, it follows that as many channels should be employed as can be operated satisfactorily during the time required for a transmitted impulse to reach the receiver. Accordingly, for different installations it is desirable to employ distributors equipped with a varying number of channels. At terminal station A shown at the left of the drawing, the transmitting segments 1 to 5 are shown connected in the usual manner to a transmitting mechanism 21. Transmitting segments 6 to 10 are connected in a similar manner to a second transmitting mechanism 22. Receiving segments 11 to 15 are connected to a printing mechanism 23, and segments 16 to 20 are connected to a similar printing mechanism 24. A brush mechanism mounted upon a rotating brush arm 31 is adapted to successively engage segments 1 to 20 and in so doing connects segments 1 to 10 with a transmitting segment T and segments 11 to 20 with a receiving segment R. The transmitting segment T is connected to a transmitting condenser K which in turn is connected to segment V ofanother section of the distributor. The common receiving segment R is connected to the vibrating armature 32 of a line relay, this armature being normally connected to a grounded source of ener y 33. One terminal of the winding 34 of file line relay is grounded and the other terminal is connected through a shaping network 35 to a segment S, which is in alignment with the segment V. The shaping network which is provided to correct the waveform of the received impulse and thereby prevent distortion may be of several types, but as shown consists of a capacity bridged by a non-inductive resistance in series with the relay winding, and an inductance in series with a resistance bridged across the relay winding. Segments V and S are of equal length and correspond to segments T and R. Upon the rotation of brush arm 31, brush 36 alternately connects segments V and S with segment X, which is joined directly to the cable conductor.

In order to control the operation of the transmitting and printing mechanisms, the distributor is provided with a third section consisting of the segments 25 to 28, arranged as shown, and adapted upon rotation of the brush arm 31 to be engaged. by the brush member 37 which successively connects these segments to'local segment L, which is connected to the groundedsource of energy 38. The local segment 25 is connected to one terminal of the operating magnet 40 .of the printing mechanism 24. Segment 26 is connected electrically to electromagnet 41 of a stepping magnet which controls the tape movement of transmitter 21. Segment 27 is connected to electromagnet 42, which controls the tape movement of transmitter 22.

Local segment 28 is connected electrically 30 in turn engages segments 1 to 5, a series of impulses corresponding for example to the Baudot code and depending upon the characters set up on the tape of transmitter 21 is transmitted through the brush 30 to transmiting segment T, and from thence to condenser K. These impulses are repeated through the segment V and pass through brush 36 to segment X, from whence they pass to the cable 0 and are transmitted as current waves to the se ment X of the distant station B. Since t e distributors are maintained in approximate synchronism, the brush 36' will just be entering upon segment S at the time the first of these impulses reaches the distant station. A circuit is therefore rovided from the cable to segment X t rough brush 36 to segment S, and thence through the shaping network 35 and the winding of relay 34 to ground. As a result of this impulse, the armature 32 will be energized and an impulse corresponding to the transmitted impulse will be sent 'from battery 33 to segment R, thence through brush 30 to receiving segment 11 which is connected to a receiving or printing mechanism 23. In a similar manner, as brush 30 passes over segments 2, 3, 4 and 5, corresponding impulses will be transmitted through segments 12, 13, 14 and 15 to set up the desired character upon the printer 23. As the brush 30 passes over segments 6 to 10, a series of impulses is supplied in a similar manner to the receiving segments 16 to 20 resulting in a corresponding character being set up on the printing mechanism 24. At the same time that brush 30 wipes over segment 6, brush 37 wipes over segment 26, thus closing a circuit from the grounded source of energy 38, through segment L, brush 37, segment 26 and electromagnet 41 to ground. 'The transmitting electromagnet 41 is therefore energized and 'operates to advance the. tape of transmit- 36 therefore, connects segment X to segment nected to the local segment L. The impulse sent over the cable, from transmitting segment 1', therefore, passes from segment X to .brush 36, to segment S, and thence through the shaping network and the winding 34 of the line relay and to ground. The operationof the relay closes the circuit from the grounded source of energy 33, armature 32, segment R, brush 30, receiving segment 11, to ground at the printing mechanism 23. As the brush 30' passes over segments 2 to 5. corresponding impulses are transmitted in a similar manner to the printing mechanism 23 to set up apredetermined character. As brush 37 engages contact there is provided a local circuit from the grounded source of energy 38, through segment L, brush 37, segment 27, and electromagnet 42 to ground. The operation of electromagnet 42 steps ahead the tape of transmitter 32, which has just completed its sending operation. Upon brush 30' wiping over contacts 6 to 10, impulses Set up in transmitter 22 are transmitted in a manner previously described to receiving segments 16 to 20. at station A and thence to'the printing mechanism 24. Upon brush member 37 engaging contact 28, a local c1rcu1t is provided from grounded source of energy 38,

through segment L, brush 37, contact 28,

and electromagnet 43 to ground. The operation of electromagnet- 43 serves to operate the printing mechanism 23 upon which the character has previously been set up.

The sending condensers K and K and the shaping networks 35 and 35' are provided for the purpose of modifying the wave forms of the transmitted and received electrical impulses to obtain most eflicient operation and overcome distortion. lVhile in the arrange ment illustrated a line relay is employed to transmit impulses to the printing mechanism, it is of course obvious that the incoming impulses can be amplified and employed directly to operate the printer.

What is claimed is:

' 1. The combination with a loaded submarine cable of a transmitter at each terminal thereof, a receiver at each terminal with the cable for a period of time not greater than that required for the transmitted signal to arrive at the receiver.

3. The combination with a loaded submarine cable'of a transmitter at each terminal thereof, a receiver at each terminal thereof, and a rotary distributor at each terminal thereof, said distributors being driven in synchronism and including means for automatically associating the transmitters and receivers alternately with the line for a period of time substantially equal to that required for the transmitted signal to reach the receiver.

4. The combination with a loaded submarine cable of a transmitter, a receiver, a sending condenser, a shaping net work, and a rotary distributor at each terminal thereof, said distributors being arranged to simultaneously and alternately associate said transmitters and said receivers with the cable for a period of time not greater than that required for the signal transmitted at one terminal to arrive at the receiver of the other terminal and including means for associating the sending condenser with the transmitter and the shaping network with the receiver.

5. The combination with a loaded submarine cable of a transmitter at each terminal thereof, a receiver at each terminal thereof, and a rotary distributor at each terminal thereof, said distributor including means for alternately associating the transmitters and receivers with the cable each for a period of time :not greater than that required for a transmitted signal to reach the receiver, and additional means for correcting the wave forms of received current impulses.

6. A telegraph system comprising a loaded cable, a pair of terminal stations associated therewith, each of said terminal stations comprising a transmitting mechanism, a receiving mechanism, and a switching mechanism including automatically operated means for alternately associating said transmitting and receiving mechanisms with the cable, each for a period of time not greater than that required for a transmitted signal to reach the receiver, and additional means for setting up code combinations of impulses on said transmitting mechanism to be transmitted successively over the cable. 7. A telegraph system comprising a loaded submarine cable and a pair of terminal stations associated with the ends thereof, each of said terminal stations including a transmitter, a receiver, and a synchronously operated distributor, one section of which is equally divided between sets of transmitting and receiving segments, the speed of operation of such distributors being such that the time occupied by the distributor brushes in passing over a set of transmitting segments is substantially equal to the time required iii) for a signal propagated at one station to arrive at the receiver of the other station.

8. A telegraph system comprising a loaded submarine cable and a pair of terminal stations associated with the ends thereof, each of said terminal stations including a transmitter, a receiver, and a synchronously operated distributor, each of said distribusaid transmitting segments and a plurality of receiving mechanisms associated with said ,recelvlng segments.

9. A telegraph system comprising a loadsociated with each end of the cable, a transmitting mechanism individual to each of said distributors and arranged to be connected simultaneously with the cable by said distributors for the transmission of impulses over the cable in opposite directions simultaneously, and a receiving mechanism at each end of said cable arranged to be connected simultaneously with the cable forrecording current impulses transmitted by the transmitting mechanisms at the opposite ends of the cable.

In witness whereof, I hereunto subscribe my name this 30th day of September, A. D.

ALLISON A. GLOKEY. 

